<p dir="ltr"><b>The research question addressed in this paper is "How to design a mobile application to help China's Generation Z to alleviate their growing anxiety and ameliorate the negative effects of death anxiety?" </b></p><p dir="ltr">Depression and anxiety are on the rise globally in the wake of the COVID-19 outbreak (Menzies, 2020). A statistical survey revealed that more than half of Chinese respondents experienced moderate or severe anxiety due to the impact of the pandemic (Wang & Pan et al., 2020). Death anxiety is becoming a psychological problem commonly faced by contemporary Chinese. To solve this issue, this research proposes the design of a mobile application that can write a will and record emotions, adding a countdown timer and emotion detection features to a private diary mobile application to alleviate death anxiety in China's Generation Z. </p><p dir="ltr">This research builds on prior evidence that investigated the current state of anxiety growing in the Chinese social context, analyzed existing app designs on mental health and anxiety relief, and designed a conceptual design for a mobile application with a countdown and mood recording function. </p><p dir="ltr">The purpose of this research is to demonstrate the prototyping and iterative process of this application. The effectiveness of this research in alleviating death anxiety is explored through an analysis of relevant literature reviews and existing design precedents. The research will also discuss the possible limitations of this research in the context of the digital age and provoke critical reflections on the future design of private diary (mental health/mood monitoring/anxiety relief) apps. </p><p dir="ltr">The results of this research address anxiety problem of China's Generation Z. This research confirms that the private diary application has a significant positive effect on intervening in users' anxiety and relieving users' emotional stress. It is proved to be an effective way to help China's Generation Z relieve death anxiety through this project.</p>