Wechat personal signature leaving someone else's mobile phone number is not fraud. According to relevant public information, fraud refers to the act of defrauding a large number of public and private property by fabricating facts or concealing the truth for the purpose of illegal possession. Whoever defrauds public or private property in a relatively large amount shall be sentenced to fixed-term imprisonment of not more than three years, criminal detention or public surveillance, and shall also, or shall only, be fined.