Phased best fit double-peaked period for 2000 SY178 of 3.3282 hr. Fitting adopted a 6th Fourier series and the order is determined by F-test. The maximum peak-to-peak amplitude is 0.56 ± 0.02. The two lower peaks have a difference of about 0.08 mag, showing 2000 SY178 has an elongated irregular shape and a light curve dominated by shape rather than albedo effects.