Just looking at the pictures, there is a resemblence. You could also add a picture of the Delta II family, starting with the Delta N and N2 that were produced under license in Japan.

Looking more closely at the H2, we see the following specs:

Launches: 7.
Failures: 2.
Success Rate: 71.43% pct.
First Launch Date: 03 February 1994.
Last Launch Date: 15 November 1999.
LEO Payload: 10,060 kg. to: 200 km Orbit. at: 30.4 degrees.
Payload: 3,930 kg. to a: Geosynchronous transfer trajectory.
Liftoff Thrust: 405,000 kgf.
Total Mass: 260,000 kg.
Core Diameter: 4.0 m.
Total Length: 49.0 m.

Stage Number: 0. 2 x H-2-0
Gross Mass: 70,400 kg.
Empty Mass: 11,250 kg.
Thrust (vac): 157,036 kgf.
Isp: 273 sec.
Burn time: 94 sec.
Isp(sl): 237 sec.
Diameter: 1.8 m.
Span: 1.8 m.
Length: 23.4 m.
Propellants: Solid
No Engines: 1. H-2-0

Stage Number: 1.
1 x H-2-1
Gross Mass: 98,100 kg.
Empty Mass: 11,900 kg.
Thrust (vac): 109,925 kgf.
Isp: 446 sec.
Burn time: 346 sec.
Isp(sl): 349 sec.
Diameter: 4.0 m.
Span: 4.0 m.
Length: 28.0 m.
Propellants: Lox/LH2
No Engines: 1. LE-7

Stage Number: 2.
1 x H-2-2
Gross Mass: 16,700 kg.
Empty Mass: 2,700 kg.
Thrust (vac): 12,390 kgf.
Isp: 452 sec.
Burn time: 600 sec.
Diameter: 4.0 m.
Span: 4.0 m.
Length: 10.6 m.
Propellants: Lox/LH2
No Engines: 1. LE-5A

The Long March is actually a family of launch vehicles. Picking the CZ3B as a representative example, we see the following specs:

Launches: 5.
Failures: 1.
Success Rate: 80.00% pct.
First Launch Date: 14 February 1996.
Last Launch Date: 18 July 1998.
LEO Payload: 11,200 kg. to: 200 km Orbit. at: 28.5 degrees.
Payload: 5,100 kg. to a: Geosynchronous transfer trajectory.
Liftoff Thrust: 304,000 kgf.
Total Mass: 425,800 kg.
Core Diameter: 3.4 m.
Total Length: 54.8 m.
Launch Price $: 70.00 million. in 1999 price dollars.

Stage Number: 0. 4 x CZ-2E-0
Gross Mass: 41,000 kg.
Empty Mass: 3,200 kg.
Thrust (vac): 83,238 kgf.
Isp: 291 sec.
Burn time: 128 sec.
Isp(sl): 261 sec.
Diameter: 2.3 m.
Span: 2.3 m.
Length: 15.3 m.
Propellants: N2O4/UDMH
No Engines: 1. YF-20B

Stage Number: 1. 1 x CZ-3A-1
Gross Mass: 179,000 kg.
Empty Mass: 9,000 kg.
Thrust (vac): 332,952 kgf.
Isp: 289 sec.
Burn time: 155 sec.
Isp(sl): 259 sec.
Diameter: 3.4 m.
Span: 7.0 m.
Length: 23.1 m.
Propellants: N2O4/UDMH
No Engines: 4. YF-20B

Stage Number: 2. 1 x CZ-2C/SD-2
Gross Mass: 55,000 kg.
Empty Mass: 5,000 kg.
Thrust (vac): 77,700 kgf.
Isp: 298 sec.
Burn time: 190 sec.
Isp(sl): 270 sec.
Diameter: 3.4 m.
Span: 3.4 m.
Length: 10.0 m.
Propellants: N2O4/UDMH
No Engines: 1. YF-22A/23A

Stage Number: 3. 1 x CZ-3A-3
Gross Mass: 21,000 kg.
Empty Mass: 2,800 kg.
Thrust (vac): 16,000 kgf.
Isp: 440 sec.
Burn time: 470 sec.
Diameter: 3.0 m.
Span: 3.0 m.
Length: 12.4 m.
Propellants: Lox/LH2
No Engines: 2. YF-75

Looking at the differences, we see the Chinese booster uses liquid fueled strap-ons verses the Japanese's solid-fueled strap-ons. The Chinese use 3 liquid-fueled stages on the core, with the first two stages using hypergolic propellants. The Japanese use two liquid-fueled stages, and both of those stages use cryogenic H2/LOX propellants. The Japanese use a single engine on the first stage to produce 109,925 kgf while the Chinese use 4 engines to produce 332,952 kgf.

There are many other differences but I hope you get the idea. In short, beyond the superficial similarities in appearance, you're looking at two very different boosters.