Crystal growth is a complex process,and until now there isn’t a satisfied real t ime observation method.Under the space high temperature in situ observation inst rument(SHITISOI),we develop a three dimensioned real time observation device for the crystal.By it,we can acquire image of crystal in three dimension,moreover,i t would provide technique for remote science control in the future space experimen t.We develop the device not only apply to real time observation also adapt to r e mote science research.We use annular quartz glass so as to in situ observe the c hange of interface.And two heater were put its upon and down,thus they form two different temperature zones.We apply to Bridgeman method crystal growth by using special lift to move the quartz crucible.Presently we have developed a pass mus t er furnace, and can get the NaNO 3 crystal.We could observe the fluid flow stat ue and the interface move by tracer particle.We get the effect of unsteady conve ction,which is important both in land and space crystal growth.