In this paper，the reliability on stability against sliding of 252 railway abutments has been calcuated with improved Mont e-Carlo method. The reliability level of active standardized design has been found. By calculating， the mean value with water and without water of concrete abutment are 4. 041 and 3. 745 respectively， the variation are Q 142 and 0. 154 respectively， the mean value with water and without water of ragstone abutment are 4. 138 and 3. 883 respectively， the variation are 0. 126 and 0. 152 respectively. Through these results，the influence on reliability of main random variables has been analyzed.