Most invalid number of database including specific symbols or Chinese characters which are not included in ASCII Character Set.These invalid data fields may bring unexpected risk to MIS or data migration.Address the problem,the paper proposed two detection methods of database nonstandard field Independent of Character Set.The one converts the field to ASCII and then compares the values between before and after.Another compares the byte length and word length.All the two methods detected all of nonstandard fields in the data table.The methods afford new effective measures to detecting and correcting invalid number in database.