We observed GRB 100302A afterglow position (Goad et al. GCN 10460, Huang et al. GCN 10461 and Cucchiarar & Fox GCN 10465) in i-band (12x300s) using 1.0 telescope at Mt. Lemmon (Arizona, US) operated by the Korea Astronomy Space Science Institute. No significant detection of afterglow in our i-band combined image at 11.0709 hours after the burst. The 3-sigma limiting magnitude is 20.8, which calibrated with five nearby USNOB stars. We also reduced R and i band images taken by Lulin 1-m telescopes. Our photometric results, combined with the i-band detection reported by Cucchiarar & Fox (GCN 10465), indicate the i-band power law index is about -0.65. Delay time filter EXPTIME Magnitude error (hour) --------------------------------------------------- 0.450 R 300s x 5 21.54 0.22 0.780 I 300s 20.02 0.12 0.873 I 300s 20.24 0.15 0.966 I 300s 20.08 0.13 1.060 I 300s 20.17 0.17 1.153 I 300s 20.34 0.19 1.357 I 300s x 4 20.31 0.17 -------------------------------------------------- This message can be cited