mRNA-based technology has been evaluated in a variety of clinical trials for the rapid control and prevention of emergencies and therapeutic indications. HC009 is a mRNA-based vaccine encoding the full-length of the SARS-CoV-2 spike protein and delivered by the QTsome delivery platform. Here, the immunogenicity, toxicity, and biodistribution of HC009 were investigated in rats. In the immunogenicity and toxicity study, rats received three intramuscular (IM) injections of HC009 at a 3-week interval followed by a 4-week observation period. In the biodistribution study, rats were given a single intramuscular injection of HC009, and the amount of the mRNA was detected in the organs and at various time points. The study results showed that HC009 could elicit effective and long-lasting humoral immunity and Th1-biased cellular responses. The mRNA of HC009 was mainly distributed in the injection site and the spleen, and no vaccine-related toxicological reaction was observed. Together, these data have shown that HC009 could induce an effective immune response with a favorable safety profile and support its further study in clinical trials.