问题还是自己解决了。设置 minPeriod="ss" 。因为我从后台返回的数据是精确到秒的,而在Amcharts中要显示到分钟。根据官方解释,须设置成秒。
<!-- It is very important to tell the category axis if it's values are date based or not.In case yes, set parseDates to true. You should also set the minimum period of your data.For example, if you have hourly data, set minPeriod to "hh". -->