The special characteristics of a silicon solid-state (P-N type) dosimeter are examined at the energy ranges of the diagnostic x-ray.The detector is made in a compact size of 35×20×15mm of Aluminium with acrylic resin surface for exposure side and the box is sealed by solid-state element.The examination revealed that the exposure dose volue were uniform in the ranges of 100 R to 10 mR, and stable to the standard dosimeter value, and maximum in sensitivity at 30 keV x-ray.The value are also depended to the temperature.This solid-state dosimeter was useful at clinical practice following the adequate correction for the diagnostic x-ray.