It is still a huge challenge for traditional Pareto-dominated many-objective optimization algorithms to solve manyobjective optimization problems because these algorithms hardly maintain the balance between convergence and diversity and can only find a group of solutions focused on a small area on the Pareto front, resulting in poor performance of those algorithms.For this reason, we propose a reference vector-assisted algorithm with an adaptive niche dominance relation, for short MaOEA-AR.The new dominance relation forms a niche based on the angle between candidate solutions.By comparing these solutions, the solution with the best convergence is found to be the non-dominated solution to improve the selection pressure.In reproduction, a mutation strategy of k-bit crossover and hybrid mutation is used to generate high-quality offspring.On 23 test problems with up to 15-objective, we compared the proposed algorithm with five state-of-the-art algorithms.The experimental results verified that the proposed algorithm is competitive.