The simplest and easiest way of drug administration is oral route. The formulation of poorly soluble compounds for oral delivery at present is one of the most frequent and greatest challenges to formulation scientists in the pharmaceutical industry. The present review relates the solid dispersion technique for bioavailability enhancement of BCS class 4 drug. the dispersion classification in this review give detail idea about the mechanism of drug to be dispersed in the carrier for solubility enhancement with different mechanism of the solubility of drug in biofluids enhancement which helps further in bioavailability enhancement of the drug to minimize dosing frequency and dose. the review also gives detailed methods for solid dispersion preparation with their recent advancement techniques as well as their different evaluation techniques. the review concludes with the suggestion for the scope of the further research with practical limitation of the solid dispersion technique with further study like practical scale up technique and poor flow and compressibility.