With the development of the mobile phone industry, mobile applications market becomes thriving. However, the immature information technology and unfriendly interface bring negative user experience (UX) to the mobile users and thus affect the service life of mobile applications, especially for the most concerned entertaining applications, mobile games. As a result, the evaluating UX and finding crucial factors of UX become a challenge. Over the last decades, numerous researches have tried to deal with this issue, but none of them has clearly identified the relations among positive-negative UX, sufficient human characteristics and specific events of applications. This paper proposes a subjective-objective evaluation method. Subjective UX of mobile games is sufficiently obtained and objective UX is verified through the electrocardiogram signals and heart rate variability. In order to reveal distinct relations among UX factors, sufficient user characteristics and categories of game events, an improved RIPPER algorithm is proposed by this paper to obtain the relations. Experiments are performed with 300 testers who played mobile parkour games for at least five minutes. The accuracy and efficiency of the proposed method have been verified through real experiments and objective measures. In addition, this paper provides an effective sampling method and a data analysis algorithm to obtain crucial UX factors for mobile applications.