THCHS30 is an open Chinese speech database published by Center for Speech and Language Technology (CSLT) at Tsinghua University. The origional recording was conducted in 2002 by Dong Wang, supervised by Prof. Xiaoyan Zhu, at the Key State Lab of Intelligence and System, Department of Computer Science, Tsinghua Universeity, and the original name was 'TCMSD', standing for 'Tsinghua Continuous Mandarin Speech Database'. The publication after 13 years has been initiated by Dr. Dong Wang and was supported by Prof. Xiaoyan Zhu. We hope to provide a toy database for new researchers in the field of speech recognition. Therefore, the database is totally free to academic users.