Abstract: The theoretical model on negative mass particles has been further explored.The positive and negative mass particles form the mass symmetry of the universe.Particles with different symbols of masses repel each other.When a negative mass particle collides with a positive mass particle of the same kind,the total annihilating reaction takes place.The vacuum state is regarded as a bound state of pairs of the positive and negative mass particles.On the basis of model,the knotty problems about the accelerated expansion of the universe and dark energy have been illustrated successfully,and the paradoxes of Olber and Sealiger have been dissolved.