In this paper, we analyzed the breakdown voltage and on-resistance of the multi-RESURF SOI LDMOSFET as a function of epi-layer concentration. P-/n-epi layer thickness and doping concentration of the proposed structure are varied from $2{sim}5{mu}m;and;1{times}10^{15}/cm^{3}^{sim}9{times}10^{15}/cm^{3}$ to find optimum breakdown voltage and on-resistance of the proposed structure. The maximum breakdown voltage of the proposed structure is $224;V;at;R_{on}=0.2{Omega}-mon^{2};with;P_{epi}=3{times}10^{15}/cm^{3},;N_{epi}=7{times}10^{15}/cm^{3};and;L_{epi}=10{mu}m$. Characteristics of the device are verified by two-dimensional process simulator ATHENA and device simulator ATLAS.