BACKGROUND: The high costs of innovative anticancer drugs hinder a number of cancer patients' access to these drugs in China. To address this problem, in 2018, the medical insurance access negotiation (MIAN) policy was implemented, when the prices of 17 innovative anticancer drugs were successfully negotiated and they were therefore included in the reimbursement list. This study aimed to explore the impact of the MIAN policy on the utilization of innovative anticancer drugs. METHODS: With monthly data on drug expenditures and defined daily doses (DDDs) of each innovative anticancer drug from January 2017 to December 2019, interrupted time series analysis was employed to estimate both the instant (change in the level of outcome) and long-term (change in trends of outcomes) impacts of the MIAN policy on drug utilization in terms of drug expenditures and DDDs. Our sample consists of 12 innovative anticancer drugs. RESULTS: From January 2017 to December 2019, the monthly drug expenditures and DDDs of 12 innovative anticancer drugs increased by about 573% (from US$8,931,809.30 to US$51,138,331.09) and 1400% (from 47,785 to 668,754), respectively. Overall, the implementation of the MIAN policy led to instant substantial increases of US$8,734,414 in drug expenditures and 158,192.5 in DDDs. Moreover, a sharper upward trend over time was reported, with increases of US$2,889,078 and 38,715.3 in the monthly growth rates of drug expenditures and DDDs, respectively. Regarding individual innovative anticancer drugs, the most prominent instant change and trend change in drug utilization were found for osimertinib, crizotinib, and ibrutinib. In contrast, the utilization of pegaspargase was barely affected by the MIAN policy. CONCLUSIONS: The MIAN policy has effectively promoted the utilization of innovative anticancer drugs. To ensure the continuity of the effects and eliminate differentiation, supplementary measures should be carried out, such as careful selection of drugs for medical insurance negotiations, a health technology assessment system and a multichannel financing mechanism.