Abstract: A optic fiber chemical sensor drug dissolution monitor (OFCSDSM) was fabricated and applied to real-time and situ monitoring of dissolution of compound chlorzoxazone tablets.One end of the bifurcated optic fibre was connected with the light source,and the other end with the detector,while the probe at the common end was dipped into the dissolving solution contained in the dissolution vessel.Data logging and processing were performed by a hyphenated computer.Recoveries of paracetamol (a component of the chlorzoxazone tablet) at 3 concentration levels (low,middle and high) were tested and results of 98.3%,102.3% and 103.1% were obtained correspondingly,with respective RSD values of 1.0%,1.4% and 0.4%.Recoveries of the main component,chlozoxazone were also tested at 3 concentration levels,and results of 108.6%,98.7% and 97.7% were obtained with respective RSD values of 1.7%,1.6% and 1.3%.Whole process of the dissolution was monitored and a dissolution curve of the drug was displayed.Related dissolution parameters could be abstracted timely.It was proved that by the use of OFCSDSM,informations of real situation of the drug dissolution process could be obtained.