The present invention discloses a method and apparatus for speech synthesis based on a large corpus. The method for speech synthesis based on a large corpus comprises: utilizing a prosodic structure prediction model to carry out prosodic structure prediction processing on input text to provide at least one alternative prosodic boundary partitioning solution; determining a prosodic boundary partitioning solution according to structure probability information about a prosodic unit in a speech corpus in the at least one alternative prosodic boundary partitioning solution; and carrying out speech synthesis according to the determined prosodic boundary partitioning solution. The method and apparatus for speech synthesis based on a large corpus provided by the embodiments of the present invention improve the naturalness and flexibility of speech synthesis.