Abstract: Objective To analyze the temporal fluctuation of crisis hotline calls with high suicide risk in Guangzhou city.Methods Information on 1 533 crisis hotline calls identified with high suicide risk from January 2008 through December 2015 were collected and analyzed with concentration degree analysis,circular distribution and chi-square analysis.Results The results of circular distribution analysis showed two periods with high frequency of high suicide risk calls in a year:from January 1st to Febuary 19th and from May 25th to December 31st;the total number of the hotline calls with high suicide risk during the two periods was 1 230,accounting for 80.2% of total calls with high suicide risk during the 8 years.The day with the greatest number of high suicide risk calls was October 7th of a year.Of all the high suicide risk calls,1 037 (67.6%)were telephoned in during the time from 11:24 a.m.to 00:20 a.m.of the next day and more calls were telephoned in around 17:52 p.m.The daily number of high suicide risk calls was significantly different during a week (χ²=19.342,P<0.05),with the highest number of 254 on Monday accounting 16.6% of total calls on all weekday and weekend days.Conclusion Centralized tendency was observed in the monthly,daily,and hourly distribution of crisis hotline calls with high suicide risk in Guangzhou city and the results provided important information for optimizing crisis hotline management and preventing suicide behaviors.