In designing a knapsack mist blower with advanced characteristics, it is required that the general drawing should be reasonable and the components ensure the technical and mechanic requirements. To damp vibration and reduce noise, there is a need for the analysis of the spectrum of vibration and noise so as to determine the character of vibration and the frequency domain to be damped on which the design is based. Besides, engineering cost analysis is used in this paper to justify the structural design and design plan so that the optimal functional characteristic and cost of the product can be decided.