The time focus of electron pulse was studied by using the time dilation framing camera. While the PhotoCathode (PC) is not pulsed, the measured temporal resolution of the camera is 80 ps. While the pulse with a 14 V/ps gradient is applied on the PC, and the delay time of the circuit is 11.395 ns, the temporal resolution is 8.8 ps. The results show that the the temporal shape of the electron signal is compressed first and then dilated. Furthermore, the relationship between the temporal resolution and the falling edge gradient of the PC pulse is obtained. While the falling edge gradient of the PC pulse is 1 V/ps, the temporal resolution is about 80 ps. It shows that the time width of the electron pulse is approximately equal to its original width while the electrons arrive at the microchannel plate (MCP). While the gradient is more than 1 V/ps, the temporal resolution is less than 80 ps. The time width of the electron pulse is dilated while it arrive at the MCP. While the gradient is 0.5 V/ps, the temporal resolution is more than 80 ps. The time width of the electron pulse is compressed.