The study of total harmonic distortion is the important factor in power electronic devices for predominately calculations and it is effects the technical issues and cost functions. The 13 level Cascaded H bridge with 1-Phase half Bridge LDN networks improving for effectiveness of analysis in THD. This paper main objective is finding the harmonic analysis with different frequencies by using data sheets and MATLAB circuits learning process. The simulation results obtained using Cascaded H bridge with LDN method for producing the 13 level output related to different THD values with different frequencies changing the load parameter values. This system explains about differences between two methods and reducing the no of switches for developing same output values, but THD values are important for design of filter combinations in power electronic devices and it is changes at different frequencies with amplitude values.THDanalysed with SPWM method in multilevel inverter.