In the face of the capricious capital market, investors necessitate more credible and precise financial analyzing instruments to discern a lucrative investment opportunity, especially in the stalk market. In general, potential investors tend to make investment decisions based on the past financial performance of a firm and its stalk price trend. Besides, the federal's policy, the firm's position in the industry, and future development promises will also be taken into concern. This article intends to introduce a plethora of financial analysis indicators and methodology, such as standard deviation, expected return rate, and CAPM, to augment our investment decisions. Highlighting the indispensable canon to disperse the risk, we discuss managing it via investing in distinct industries. What's more, we used Delta airline and Tesla as examples throughout our articles to strengthen our stands. To increase our articles' practicality, we have researched the challenges and changes brought to the automobile and aviation industry against the COVID-19 circumstances. We hope this article will be propitious to investors to evaluate the responses of both Delta airlines and Tesla and discuss bailout policies enacted by the federal.