In this study, the characteristics of fluid, which flow through a channel with obstructions due to sediments or repair-packing demand, were investigated by numerical method. The results showed that the characteristics of fluid changed when the fluid flows through the obstacles. The pressure increased significantly on the upstream of the obstacle. On downstream of the obstacle, the pressure was gradually increased from a negative value, and the velocity was gradually accelerated to the outlet velocity. The obstacle leaded to the reduction of the cross section of the channel. The fluid velocity was increased to the maximum value, and the pressure dropped to the minimum value. After through the obstacle, the pressure increased, separation phenomenon appeared and the fluid velocity gradually slowed down to the outlet velocity.