Dear Maxime,
Thank you very much for your questions.
Please kindly be advised most scenic spots in China do not agree to pay by credit card, but some scenic sports with high ticket prices accept credit card for payment.
Since the admission of Jiuzhaigou valley is high, they accept payment by credit card. Since you are a foreigner and your credit card is overseas card, we are not sure whether they could charge from foreign card or not, but you could have a try. If it does not work, you could withdraw cash from the ATM at the entrance.
Hope the above is clear and helpful.
Should you have any questions, please do not hestiate to contact with us.
Best regards
Sophie Huang
Top China Travel