A hybrid sensor network can be utilized to transfer multiple traffics with diverse delay and loss requirements. To satisfy the worst-case delay and loss requirements, the network has to service each category of traffic according to its characteristics and quality of service (QoS) requirements. So, we consider a hybrid sensor network that is responsible for carrying burst traffics taking place for a short period of time, as in event-driven sensor networks, and low-rate traffics occurring periodically, as in time-driven networks. The main problem in these networks appears when the critical events happen. These events intrinsically are burst traffics. So, probably they can bring about local congestion in the zone that they occur. Existence of packets belonging to other applications can intensify this congestion. As a result, the quality of the radio channel is affected, traffic services degrade and packets are delayed and dropped regardless of their priority. So we need an algorithm to decrease the probability of congestion. Also, in the presence of congestion, it should hinder low priority data from making the situation worse. In the thesis we introduce a simple algorithm for sensor nodes that satisfies the service requirements of different kinds of traffics. By using this algorithm, packets with the same priority, generated after an event, are delivered to the sink with bounded and almost equal delays.The algorithm combines a specific time framing pattern, to prevent congestion, with a medium access scheduling method. This method assigns timeslots proportional to the importance and QoS requirements of the traffic, to differentiate between the traffics.The proposed algorithm adapts medium access scheduling proportional to the importance and QoS requirements of the traffic in each node. So, the access pattern is dynamic and changes proportional to the mix of traffic at each time. Besides, our algorithm schedules the transmission of packets through a specific framing pattern to reduce the probability of congestion. This framing strategy is used to decrease congestion which is the main obstacle to satisfy QoS. Simulation results shows that this algorithm provides a bounded-delay framework for delivering different kinds of traffics and each traffic category experience delays proportional to its sensitivity to delay Key words: Wireless Sensor Networks , Quality of Service, Bounded Delay, Congestion, Framing Startegy.