We investigate a Markov modulated fluid queueing system with strict pr
iority. The input process is composed of two fluid flows which are sto
red in buffer-1 and buffer-2, respectively. The rates of these fluid f
lows depend on the current state of a finite state Markov chain. Buffe
r-1 has full assignment of priority (=strict priority) for service and
so buffer-2 is served at a residual service rate when buffer-1 is emp
ty. We explicitly derive the stationary joint distribution of the two
buffer contents in the system by a spectral decomposition method. In t
he case of a two-state Markov chain, the joint distribution is explici
tly expressed in terms of the system parameters. Also the joint moment
s and tail distributions of the two buffer contents are obtained and s
ome numerical examples are presented.