SELECT 
name, --参数名
xtype,--数据类型
length,--数据长度
isoutparam,--参数类型：入参0/出参1
isnullable--是否允许为null
FROM syscolumns where ID in    
(SELECT id FROM sysobjects as a  
WHERE OBJECTPROPERTY(id, N'IsProcedure') = 1    
AND id = object_id(N'[dbo].[存储过程名]'))