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The Mark-Houwink-Sukaroda (MHS) equation [r|J = K Mva is a very important relationship to relate polymer dilute solution's intrinsic viscosity and polymer's viscosity average molecular weight. But for a wide range of polymer (copolymer) - solvent systems, the constant K and exponent a values are usually not sufficiently available. Fox - Flory and Van Krevelen dilute solution theories are employed to correlate K and a values under different temperatures therefore prove that MHS constant K and exponent a are temperature dependent for polystyrene and styrene-co-maleic anhydride. For polystyrene, the exponent a value changes from 0.7165 at 25C to 0.7327 at 45C, the literature value at 25C is about 0.72; K value changes from 0.0128 at 25C to 0.0117 at 45C, the literature value at 25C is about 0.0135. For 92/8 poly(styrene - co - maleic anhydride), the exponent a value changes from 0.7301 at 25C to 0.7414 at 45C; K values changes from 0.0115 at 25C to 0.0108 at 45C. For 86/14 polystyrene - co - maleic anhydride), exponent a value changes from 0.7469 at 25C to 0.7593 at 45C; K values changes from 0.0102 at 25C to 0.00965 at 45C. Einstein viscosity equation is a fundamental equation to calculate polymer solution viscosity from viscometric data: r|=n (l + 0.5(f)) / (H)2 s A GPC universal calibration curve based on polystyrene standards was used to work out the viscosity average molecular weight for the sample 92/8 and 86/14 poly(styrene - co - maleic anhydride); the values fall nicely into the range which is suggested by the commercial manufacturer. For 92/8 poly(styrene - co - maleic anhydride), Mv is 2.4* 105 g/mol, for 86/14 poly(styrene - co - maleic anhydride), Mv is 1.1*105 g/mol. Theoretically, solubility parameters are calculated to predict the exponent a values , but the results are not as good as the experimental method. Therefore, some new models might be suggested to predict and correlate the MHS constant K and exponent a more reasonably.