The invention discloses an environment-friendly gas sampler. The environment-friendly gas sampler comprises an outer cylinder, a piston body, an exhaust pipe and a power transmission mechanism, wherein a vent hole is formed in the tail of the outer cylinder, the piston body is arranged in the outer cylinder in a sliding mode, and the exhaust pipe is arranged at the front end of the outer cylinder and is communicated with the outer cylinder; the power transmission mechanism is arranged inside the outer cylinder and comprises a first chain, a second chain, a first idle wheel, a second idle wheel and a motor, one end of the first chain is connected with the piston body, the other end of the first chain is connected with the first idle wheel, one end of the second chain is connected with the piston body, the other end of the second chain is connected with the second idle wheel, and the motor drives the first idle wheel and/or the second idle wheel to rotate. The environment-friendly gas sampler has the advantages of being easy to operate, high in sampling purity and beneficial for improving test efficiency.