The invention discloses a quinolizinones compound which comprises an optical isomer, a raceme and a cis-trans-isomer and a random combination or pharmaceutical salt thereof. A structure of the quinolizinones compound is as shown in a formula I: (with reference to the specification), wherein one of V and Y is O, and the other one of V and Y is CR8R9; R8 and R9 respectively independently are hydrogen or C1-6 alkyl. The invention further discloses a preparation method and application of the compound in the formula I. The compound in the formula I can obviously reduce a HBsAg (Hepatitis B surface antigen) level in vivo and meanwhile, inhibit replication of a HBV (Hepatitis B Virus), wherein when V or Y is O, solubility of the compound is obviously improved, the compound has excellent medicinal attributes and meanwhile, is also low in toxicity, pharmacokinetics and pharmacodynamics functions are improved, efficiency of combining with the HBV can be greatly improved, and a clearance ratio of the HBV in vivo can also be further improved.