let info = wx.getSystemInfoSync();
if(compareVersion(info.SDKVersion, '2.11.1') >= 0){
    if(!this._adObj){
        this._state = AdState.LOADING
        let obj = {
            adUnitId: this._adUnitId,
            adIntervals: Number(this._intervals),
            style: {
                left: 0,
                top: info.screenHeight / 2,
                fixed: false
            }
        }
        console.log(obj)
        this._adObj = wx.createCustomAd(obj);
        this._adObj.onError((this.onError).bind(this));
        this._adObj.onLoad((this.onLoad).bind(this));
    }
    return true
}
else{
    this._state = AdState.ERROR
    this.onError('SDK版本过低：'+ info.SDKVersion)
}

无论怎么设置style的值，就是显示在左上角！