Novel potassium ion selective electrodes (K~+ISEs) and cDNA array sensors based on porous silicon (PS) have been developed.The calibration curve for the K~+ISEs is linear within a wide range of pK=2.0～6.0 with the slope of 56 mV per decade,which is near Nernst response.The response time and detection limit are within 31 s and 0.5μmol/L,respectively.The selective coefficient for Na~+ is-3.8,satisfies the requirement for the assay of blood potassium.The response variation is within 2 mV during 2 months.The binding capacity,the dynamic range and the detection limit of the DNA sensors were improved by replacing glass slide with PS substrates.The cDNA array sensors can bear 80℃of high temperature,75% of humidity,3.6 kLx of irradiation and keep stable within 10 days when they are exposed in air.Good performances of the K~+ISE and the cDNA array sensor are attributed to the large internal surface area and the easily modified microstructure of PS. Novel potassium ion selective electrodes (K ~ + ISEs) and cDNA array sensors based on porous silicon (PS) have been developed. The calibration curve for the K ~ + ISEs is linear within a wide range of pK = 2.0 ~ 6.0 with the slope of 56 mV per decade, which is near Nernst response. The response time and detection limit are within 31 s and 0.5 μmol / L, respectively. The selective coefficient for Na ~ + is-3.8, satisfies the requirement for the assay of blood potassium The response variation is within 2 mV during 2 months. The binding capacity, the dynamic range and the detection limit of the DNA sensors were improved by replacing glass slide with PS substrates. The cDNA array sensors can bear 80 ° C of high temperature, 75 % of humidity, 3.6 kLx of irradiation and keep stable within 10 days when they are exposed in air. Good performances of the K ~ + ISE and the cDNA array sensor are attributed to the large internal surface area and the easily modified microstructure of PS.