When observing the transiting extrasolar planets , we discovered a new W UMa type binary GSC 03553-00845 .
Following observation was carried out using the 1m telescope at Weihai Observatory of Shandong University .
Complete BVR light curves were determined .
Using the W-D program , we analyzed the light curves .
Photometric solution reveals that GSC 03553-00845 is a W-subtype W UMa type binary with a mass ratio of q = 2.904 , it is an overcontact binary system by a contact degree of f = 29.5 \% with a small temperature difference between the components ( \Delta T = 206 K ) indicating a good thermal contact between the components .
More observation of GSC 03553-00845 is needed in order to analyze the light curve variation and orbital period change .