n this paper a model is derived to perform a linear analysis of density-wave and excursive instabilities in boiling channels. A three-node, lumped parameter thermal-hydraulic model of the channel is considered together with a two-node lumped parameter model of the heater. The conservation equations for homogeneous flow are integrated along the channel axis to get a system of integro-differential equations in which some terms are simplified in order to obtain a system of ordinary differential equations. The equations are then linearized and an expression of neutral stability boundary in a closed form is obtained. Quantitative and qualitative results from linear analysis are in good agreement with those from other models available in literature.