Intensity Modulation Radiation Therapy (IMRT) become the essential role of radiation therapy currently, therefore, quality assurance is indispensable prior to IMRT dose delivery.This study described how to identify the coincidence of desired planning isodose curves with film experimental results by using a mathematical fractal dimension characteristic method to avoid the errors caused by visual inspection.Plato is the treatment planning system utilized to implement IMRT for cancer treatment and use Elekta precise linear accelerator stop and shoot technique to deliver desired dose.Once the desired dose are delivered to AgBr film by Linear accelerator, the developed films were analyzed by PTW FIPS laser densitometer, then the optical density distribution were converted into isodose curves based on H-D curves.These films isodose curves were acquired to Osiris (Geneva University Hospital) software to aim directly on single interested dose curve for fractal characteristic analysis and the results were compared with the corresponding planning desired isodose curves for fractal dimension analysis so as to broach a criterion to determine the coincidence in between planning and measurement.The film measured isodose curves and computer planning curves are deemed identical in dose distribution if their fractal dimensions are within some criterion which implicate that fractal dimension is a unique fmgerprint of a curve in checking planning and film measurement results.Dose measured result of film is presumed to be the same if their fractal dimension are within 1%.The comparison of treatment planning isodose distributions and film dosimetry measurement can be more accurately done by fractal dimension numerical analysis, and furthermore mathematic way to do comparison reduce visual inspection discrepancy.This quantitative rather than qualitative comparison procedure will help decrease errors in dosimetry verification.