It shouldn’t be written like this. Datatables has its own method to refresh. Generally speaking, there is no need to write ajax manually

$('#_list').DataTable({
    dom: "Brtip",
    serverSide: true,
    processing: true,
    order: [[3, 'desc']],
    ajax: {
        url: URL_PREFIX + schema.API.UM_LIST.url,
        type: 'get',
        data: function (data) {
            // data['conditions'] = $('#_query_form').serializeArray();
            data['keyword'] = self.keyword
            data['workGroupID'] = self.workGroupID
        },
        error: function(resp) {
            if (resp.status == 403) {
                toastr.info('没有权限访问')
                self.loadUser()
            }
        },
        beforeSend: oauthHeaders
    }
）

When the data changes (when the button is clicked), you should set the value into data 方法里，然后调用$('#_list').DataTable().ajax.reload()It will be refreshed