The purpose of this study is to clarify the characteristics of observed polarization parameter by X-band MP radar (X-MP) over Hokuriku region. Especially, this study analyzed the raindrop size distribution (DSD) using observed horizontal polarization Zh, measured differential reflectivity ZDR and specific differential phase shift KDP as polarization parameter. As a result of analysis of observed polarization parameter, ZDR and Zh have liner relation by heavy rainfall, and ZDR and Zh may be formulated raindrop and snowflake by snowfall and graupel. Precipitation intensity R and ZDR have correlation relation by heavy rainfall, however snowfall haven’t that, especially same value of ZDR have widely distributed R by snowfall.