This research aims to see student perception of online lectures since hit by a new disease known as Covid-19 using mix method. This study employed a qualitative approach to seeing student perceptions of online application use in online lectures while a quantitative approach to seeing student understanding of the online lecture material. Data is gathered through the distribution of poll, questionnaire, and summative tests. The results concluded that students prefer to use WhatsApp Group as an online application in an online lecture based on 4 categories of assessment, namely, display, ease of access, quota usage, and file size. Then, in the summative test, 31% of student test results are in the very high and high category, in the category of a percentage of 42.8% student test results. Last, in the low and very low category, the percentage of student test results was 25.8%. To sum up, this online lecture can be continued and combined with face to face lectures with more effective planning in line with Covid-19 emergencies.