In this work, we present 8523 pairs of R-band optical photometry observations for the quasar 3C 454.3 made during the period of 2006 October - 2018 February on the 70cm meniscus telescope at Abastumani Observatory, Georgia, to study its intraday variabilities (IDVs) and long-term variations, and we have come to the following results. (1) We detected 10 outbursts, a {Delta}R=3.825mag variation, and some IDVs. The IDV timescales are from 4.1 to 285 minutes, with the corresponding variability amplitude being A=2.9%-43.67%. The amplitude increases with IDV timescale. (2) The largest variation over a 1 day timescale is {Delta}R=1.38mag. (3) The IDV timescales suggest that the emission sizes are from 8.9x10^13^cm to 6.20x10^15^cm, and the magnetic field strengths are B=0.18-0.79G. (4) Period analysis results show three possible long-term periods, p=3.04+/-0.02yr, p=1.66+/-0.06yr, and p=1.20+/-0.03yr in the optical light curve. We adopted the accretion disk models and the lighthouse models to period p=3.04+/-0.02yr: in the accretion disk models, the binary black holes have masses M=1.17x10^9^M_{sun}_; in the lighthouse models, we used two boosted jet flux densities to fit the observational light curve. (5) WWZ analysis gives some short-period (high-frequency) signals associated with strong bursts (JD2454302 and JD2454521) with variable frequencies and lasting for the entire observation time span (11.3yr).