Surface plasmon resonance (SPR) is a technique, which is extremely sensitive for changes of dielectric characteristic of thin biology layers, present on top of metals, which supports SPR. This fact defines increased interest to development of immunosensors, based on this effect. The working characteristics of such sensors are dependent on many factors, both physic peculiarity and stable surface characteristics of the metal layer, which supports plasmon oscillation (silver, gold), is primary. The experiments show that type of treatment of glass substrate can change significant silver properties such as plasmon carrier and define character of absorption activity to protein molecules. Sensitivity of SPR immunosensors for change of adsorption cover thickness dependents of pH and ionic strength of protein solution also of silver surface hydrophilicity or hydrophobicity. In particular, we see a bovine serum albumin (BSA) adsorption maximum for such technology parameters: ion-plasma treatment before silver evaporation on the glass slides, pH equals 5, ion strength 20 mmol, and the surface of the silver must be highly hydrophobic.