Ca doping effects in YBa2Cu4O8 (124) phase are investigated by the citrate pyrolysis method under both atmospheric and high oxygen pressure. The decomposition temperature of (124) to the Y2Ba4Cu7O15−δ (247) and the YBa2Cu3O7−δ (123) phases decreases with Ca doping. The onset Tc measured by DC susceptibility increases linearly from 81K to 89K with increasing Ca content, x, from x=0 to x=0. 15 in nominal compositions Y1−xCaxBa2Cu4O8. The orthorhombicity; 2(b−a)/(b+a) decreases linearly with increasing x. EDAX analysis for individual grains convinced us that Ca is entering the structure, but its substitution for Y in the (124) phase seems rather unlikely.