Platform waste briquetting machine is one of the new type of mechanical equipment which has a high working efficiency and a long running time in the city garbage transfer station.It relies on the hydraulic system driver to complete action.The working principle of the hydraulic system was analyzed. Aiming at low reliability and frequent breakdown of the hydraulic system of the platform waste briquetting machine, the degree of reliability was calculated, the average working time without breakdowns was analyzed. With the help of MATLAB software, the reliability law of the hydraulic system in different working times was gotten.