Abstract: A Virtual Sensor estimates product objective or process conditions using mathematical models rather than and sometimes in conjunction with physical sensors. These mathematical models use other physical sensor readings to calculate the estimated property or condition. Virtual sensor may provide flexibility, cost effective solutions, promote diversity, ensure security and increase manageability. In this work, data fusion is performed and privacy gets increase in virtual sensor. Data fusion is often performed in order to reduce the overall message transmission from the sensors toward the base station. Time slotted voting mechanism is used for data fusion. This work investigates the problem of data fusion assurance in multi-level data fusion or transmission in this paper. Different to a recent approach of direct voting where the base station polls other nodes directly regarding to the received fusion result, this work propose a scheme that uses the time-slotted voting technique. In this scheme, each fusion node broadcasts its fusion data or vote during its randomly assigned time slot. Only the fusion result with enough number of votes will be accepted. Thus, our scheme eliminates the polling process and eases the energy consumption burden on the base station or the fusion data receiver, which could well be the intermediate nodes. In this work, for security plumstead’s algorithm is used to overcome against threat and attack