1. A voiceprint authentication method, comprising: displaying a first character string to a user, wherein the first character string comprises a predilection character preset by the user and a non-predilection character, and the predilection character is displayed as a symbol corresponding to the predilection character in the first character string; obtaining a speech of the first character string read by the user; performing a speech recognition on the speech of the first character string to judge whether a speech of the symbol in the speech of the first character string corresponds to the predilection character; obtaining a first voiceprint identity vector when the speech of the symbol in the speech of the first character string corresponds to the predilection character; and comparing the first voiceprint identity vector with a second voiceprint identity vector registered by the user to determine a result of a voiceprint authentication.