This study analyses the determinants of interest rates in the cryptocurrency lending market using a unique database from the Decentralised Finance platform. We confirm the existence of both mediation and moderation effects in the cryptocurrency lending market by employing a moderated mediation model. First, the empirical results show that the interest rate is closely related to the loan-to-value ratio, which works as the mediation variable in lending. Second, the interest rate reveals a clear connection with price fluctuations of Bitcoin. This brings up the momentum phenomenon in the lending process and incentives borrowers to acquire more money, leading to pro-cyclical speculation. Third, the lending amount reflects a moderation effect in the lending market, and the net effect of the currency price on the interest rate turns negative when the loan amount exceeds a threshold, resulting in the ‘seesaw’ effect in cryptocurrency lending. The above findings confirm that cryptocurrency lending reflects a certain degree of option characteristics and complies with the risk-debt model, which provides more evidence for understanding the momentum phenomenon and investor behaviour in the cryptocurrency lending market.