Hi gaobest,

Details here;
http://www.easyjet.com/EN/Planning/baggage.html

One piece of handbaggage ( no weight limit- ie if you can lift it onto the overhead bins then you can take it on board) with a size limit of 55x40x20 ( but the usual liquid limit applies)

Regards

TBS

PS I last flew with them a couple of years ago. For a LCC they are ok esp fora shortish flight ( you have to pay for food and drinks but the aricraft was very new and tidy)