One-dimensional little-area Si PIN detectors array for high energy X-ray measurement was developed. The sensitivity, linear output current and time response of the Si PIN were calculated theoretically and also simulated using MC software EGSnrc. According to the theoretical study, little-area Si PIN detectors array can be used to detect high intensity and high energy X-ray with better spatio-temporal resolution(3 mm-8 ns). Primary experiments were carried out based on the theoretical design on “Dragon-Ⅰ” linear induction electron accelerator using the Si-PIN photoelectric cell and the corresponding amplifier. Rreasonable response of Si-PIN photoelectric cell was gained for optimum design of practical one-dimensional little-area Si PIN detectors array.