The invention provides a game log based user gender determination method and system. Different from an existing method, the game log based user gender determination method is characterized in that game gender polarity is introduced, and user gender is speculated through a weighting method; the game gender polarity can be directly acquired by making statistics of a specific name of a user use game, and user gender accuracy measured according to the game gender polarity is quite high; model mining performed on existing user information construction data is not needed, special training on the model is omitted, the gender of a corresponding user can be accurately acquired through simple statistics and calculation, use of complex models is avoided, and excessive system cost is avoided; with the method, the user can be accurately subjected to user group positioning with low cost by a game operator through log information, the game is pushed in a targeted manner, and running cost is greatly reduced; meanwhile, user experience can be enhanced.