To improve the piston life and the whole engine performance by using piston cooling jet (PCJ) has become one of the key technologies of high thermal efficiency engine. The effects of PCJ opening and closing of oscillating cooling pistons with different compression ratios on combustion and emission performance were studied through the experiment on a 1.5 L turbocharged direct injection gasoline engine. The results showed that the friction mean effective pressure (FMEP) increased by 8%, the combustion center advanced, the incylinder maximum combustion pressure increased, and the specific fuel consumption at medium and high load slightly improved due to the effects of combustion and FMEP after turning on PCJ under different operating conditions and 12.5 compression ratio. For the emissions, turning on PCJ increased the emissions of HC and NO_x. The effect on CO emission was related to the operating conditions, but the change was very small. At medium speed and load, turning on PCJ with 12.5 compression ratio would lead to the better improvement of combustion performance, the larger reduction of fuel consumption, the smaller increase of NO_x, but the larger increase of HC compared with PCJ with 15 compression ratio.