A novel approach for generating n×m-scroll chaotic attractors is proposed. The grid multi-scroll chaotic system is constructed by triangular wave series and step function sequence, and the value of the turning point and the balance point in above function are found. Basic dynamic properties of the system are investigated via theoretical analysis and computer simulation. Modularization design of circuit based on field programmable gate array (FPGA) was used to realize the chaotic system, then the relevant experimental results are given. Circuit experiment is identical to computer simulation, so chaotic characteristic is verified.