This paper studies the optimal competitive strategy and risk reward model for online financial leasing problem by using online algorithm and competitive analysis method, of which the asset ownership of the assets may be transferred to the lessee after a certain lease time. We first obtain the optimal offline solution of this problem. According to the relation among the given leasing time, purchase price and rent cost, we present three online strategies and analyze their competitive ratios respectively. Finally, under the formwork of online risk reward proposed by AlBinali, we propose two kinds of forecast and their optimal online reward strategies.