ZnO　is　a　direct　wide-band　gap　semiconductor　with　Eg=3.3　eV,　which　has　high　saturation　velocity　and　is　radiation　tolerant　as　well.　It　can　be　expected　being　utilized　for　the　room　temperature　nuclear　radiation　detector.　In　this　paper,　we　fabricate　the　p(+)-Si/n-ZnO　abrupt　heterojunction　and　study　the　Xray　detection　properties.　The　I-V　characteristics　were　measured　in　the　temperature　range　of-　40　degrees　C-　40　degrees　C.　The　built-in　potential　and　the　interface　state　density　are　separately　calculated　to　be　0.25　eV　and　2.1x1011　cm-2　from　the　temperature　dependent　dark　current.　The　detector　exhibits　photovoltaic　behavior　and　shows　linear　photo-current　response　to　the　incident　X-ray　intensity.　The　open-circuit　voltage　is　0.21　V　and　the　short-circuit　current　is　0.15　A　under　the　X-ray　dose　rate　of　1.53　Gy/s.　The　sensitivities　of　the　detector　are　95　nC/Gy　and　115　nC/Gy　at　the　bias　voltages　of　OV　and-5V　respectively.　The　transient　response　presents　the　fast　and　stable　response　of　the　detector　to　the　X-ray.