Yes it will - pilates is an excellent way to build muscles, which will increase your metabolism and thereby burn fat. But I would also recommend you to do cardio as well, like biking, running, powerwalks, swimming, dancing.. More movement than muscular pressure. This will burn more fat. By combining cardio and muscle training some times a week you will get a more lasting result! Remember to have at least two days a week when you let your body rest. :)
I wish you all the best! xx