The invention provides a shock absorber. Two oil cylinders are connected through a high-pressure oil pipe, vibration generated by a forklift is converted into oil pressure through a first oil cylinder and then transferred to a second oil cylinder by flowing of hydraulic oil, and an elastic effect of a compressed spring of the second oil cylinder is utilized to conduct reset, so that under effects of vibration force of an automobile body and reset force of the compressed spring, the hydraulic oil is frequently from the first oil cylinder to the second oil cylinder, and therefore, the vibration attenuation aim is achieved. A physical principle with equal pressure is utilized to enable the oil cylinders to be manufactured to be small, further an installation space and adjustability are scattered, and simultaneously, in the process of vibration attenuation, the shock absorber guarantees bearing force of an explosion-proof forklift.