We have investigated the processes of both nonrelativistic and relativistic jet-cloud collisions using a relativistic hydrodynamic simulation code. Several runs were performed to study different aspects of these kinds of collisions. Simulations show that the collisions involve two kinds of processes: reflection and bending. Collisions of relativistic jets and high-Mach-number nonrelativistic jets appear as reflections, while the collisions of low-Mach-number nonrelativistic jets show a reflection feature at their early stage and a bending feature at their late stage. Downstream of the collisions point the flow is still supersonic. In the bending cases, the original supersonic state is maintained all the time, while in the reflection processes, the supersonic condition of the downstreams flow is re-established by high pressure. The deflection angle is not fixed; it depends on almost all parameters involved in the collisions. Even for a particular collision process, its deflection angle is not fixed, but rather changes with time. Two results are noticeable: (1) the deflection angle can be greater than 90deg ; (2) in the collision region of a reflection process, the temperature is high and the jet material suffers rapid deceleration and reacceleration.