in the festival还是on

用on the festival也可以，不过较少 ，at the festival/in the festival都可以 ；

英语要求在具体某一天用on,而节日通常也是某一天,所以用on合适.决不会用上at.

in the festival 在节日里

The concert will tie in with the festival of dance taking place the same weekend.

音乐会将和周末举行的舞蹈会演同时进行。

There are over 350 films in the Edinburgh Film Festival this year.

今年爱丁堡电影节有超过350部影片参展。

With red flags fluttering everywhere in celebration of the festival, the square looked truly magnificent.

节日的广场到处红旗飘扬，显得格外壮观。

Even if you book/ reserve tickets in advance during the Spring Festival, you may still fail to get one.

在春节期间即使提前订票，你也仍可能买不到。