Abstract: Some basic concepts on the evolvable hardware（EHW）is briefly introduced．A novel chromosome representation scheme for EHW based on the expression of product term of a logical function is presented and discussed，along with a relevant prototype of the function level field programmable gate array（FFPGA），which mainly consists of a core of RAMlook-up table and several output logic macro cells（OLMC）and can be configured in field to implement various kinds of combinatorial and sequential logic function．Some theoretical analyses and experimental results showed that the novel chromosome representation scheme and the prototype of FFPGA matched very well for lowering the computation demands，and remarkable improvements on speed and realizable size of evolution design can be obtained by online evaluation of fitness using a relevant hardware platform．