Eu2+complex centre in Ca1-xBaxF2crystals was studied with different values of x. And a new kind of ESR centre attributed to Eu2+-Ba2+complex was found at room temperature. The determined spin Hamiltonain parameters are g=1.995+-0.001, B02= 117.6(G), B22= 16.1(G), B04= 0.24(G), B24= 4.63(G), and B44= -3.47(G). Approximate hfs constants are |A151| = 37(G) and |A153| = 16.4(G), respectively. The ESR signals grew with x, but the fine structure spectra were broadened and finally disappeared as well as usual cubic Eu2+ones.