A cocrystallization technique was utilized to improve the performance of lobaplatin, and five cocrystals of lobaplatin with a variety of flavonoids, including quercetin, myricetin, fisetin, naringenin, and luteolin, were successfully obtained. The solubility, dissolution, and stability of the cocrystals were further evaluated, the results presented that the cocrystals have reduced solubilities, slowrelease rates, and delayed hydrolysis performances compared to lobaplatin. Meanwhile, the solubilities and dissolution rates of the flavonoids were dramatically improved. In addition, CCK-8 assay was used to evaluate the antitumor activity of the cocrystals, which shows that the cocrystals of lobaplatin-luteolin monohydrate, lobaplatinmyricetin monohydrate, and lobaplatin-fisetin monohydrate exhibit superior performances to lobaplatin. These findings may provide a promising solution for overcoming some weaknesses of the parent drugs.