This study examines the effects of Task-based Language Teaching (TBLT) in 52 non-native Mandarin learners of Mandarin beginning level learning motivation and the associated factors affecting their learning motivation. Mix method design was applied in the research. Quantitative questionnaire data were analyzed using paired sample t-test to examine the differences between pre-treatment survey and first cycle post-treatment survey, and between first cycle post-treatment survey and second cycle post-treatment survey. Semi-structured interview was conducted to 11 different grade-based learners among the 52 learners in the three stages of surveys to define factors affecting learning motivation. The findings reveal that there was nonstatistical decrement in learning motivation between pre-treatment survey and first cycle post-treatment survey (t(51)=1.04, p>0.05), and statistical increment between first cycle post-treatment survey and second cycle post-treatment survey (t(51)=-3.52, p<0.05). The findings of the interview show that learners? learning motivation is affected by the application of TBLT, busy schedule and support from Mandarin native speaker. As conclusion, the study indicates that TBLT can increase learners? learning motivation in long term application. The study also implicates that TBLT can perform well with sufficiency language input task and Mandarin native speakers? support before the output task.