在toolbar中配置：buttonAlign : 'center'即可,

//定义保存工具栏
var cancelRegularMeetingToolbar = new Ext.Toolbar({
buttonAlign : 'center',//这里是居中
    items:[
        // '->',//这里是居右
        {
            text : "确定",
            iconCls : 'icon-save',
            handler : function() {
                var records = cancelRegularMeetingList.getSelectionModel().getSelections();
                var saveMask = new Ext.LoadMask(Ext.getBody(), {
                    msg: '正在保存数据，请稍后...',
                    removeMask: true //完成后移除
                });
                saveMask.show();
                Ext.Ajax.request({
                    url: "zhbg/hysgl/hysxxwhAction_cancelRegularMeetingSave.action",
                    params: {
                        HYSXXGLID: records[0].get("HYSXXGLID"),
                        HYSMC: records[0].get("HYSMC"),
                        QXR: UserInfo.userName,
                        QXRID: UserInfo.userId,
                        QXRQ: cancelRegularMeetingQueryPanel.getForm().findField("LHRQ").getValue(),
                        LHMC: records[0].get("LHMC")
                    },
                    method: "POST",
                    success: function (response) {
                        Ext.Msg.alert("信息", Ext.util.JSON.decode(response.responseText).msg);
                        // cancelRegularMeetingQueryPanel.getForm().reset();
                        cancelRegularMeetingList.getStore().remove(records[0]);
                        // cancelRegularMeetingWin.hide();
                        saveMask.hide();
                    },
                    failure: function (response) {
                        Ext.Msg.alert("警告", Ext.util.JSON.decode(response.responseText).msg);
                    }
                })
            }
        },'-'
        ,
        { text: "取消",
            iconCls: 'icon-close',
            handler: function () {
                cancelRegularMeetingQueryPanel.getForm().reset();
                cancelRegularMeetingList.getStore().removeAll();
                cancelRegularMeetingWin.hide();
            }}
    ]
});

如果这种方式不起作用，还有唯一一种方法就是打空格了，前面那种方法是不起作用，我用了打空格后可以居中了

Ext.Toolbar中元素居中_ico