This paper presents a review of different Artificial Intelligence (AI) methods which are one of the latest computational intelligent techniques to solve optimal power flow (OPF) problems. OPF is one of the most vital tools for power system operation analysis, which requires a complex mathematical formulation to find the best solution. Conventional methods such as Linear Programming (LP), Newton Raphson (NR) and Non-Linear Programming were previously offered to tackle the complexity of the OPF. However, with emergence of AI methods, many novel techniques such as Artificial neural network (ANN), Fuzzy Logic (FL), Genetic Algorithm (GA), Evolutionary Programming (EP), Ant Colony Optimization (ACO), Particle Swarm Optimization (PSO), Bacterial Foraging Algorithm (BFA), and Artificial Bee Colony (ABC) have also received great attention. This paper gives detailed discussion of AI based optimization techniques to solve OPF problem which are more effective.