The effect of BaCu(B2O5) (BCB2) addition on the shrinking process and microwave dielectric properties of 0.85BaTi(4)O(9)-0.15BaZn(2)Ti(4)O(11) (BZT) ceramics were investigated by the conventional solid-state ceramic route. Adding BaCu(B2O5) into 0.85BaTi(4)O(9)-0.15BaZn(2)Ti(4)O(11) ceramics led to the formation of two new phases: Ba4Ti13O30 and BaTi(BO3)(2). The densification of the 5-15 wt% BaCu(B2O5) + BaTi4O9-BaZn2Ti4O11 ceramics sintered at approximate 900 degrees C for 2 h was attributed to the liquid phase sintering mechanism formed by the meltdown of BaCu(B2O5). The addition of BaCu(B2O5) also increased the shrinkage rate and promoted the grain growth. Because of the improved densification, the dielectric constant of the samples sintered at 900 degrees C was increased from 29.5 to 32.2 with increasing BCB2 from 5 wt% to 15 wt%. However, the Qxf value decreased sharply from 27,600 GHz to 15,900 GHz due to the progressively increased Ba4Ti13O30 as well as the whisker glass phase. At last, good microwave dielectric properties with values of epsilon(r) = 30.9, Q x f= 20,200 GHz and tau(f) = +11.7 ppm/degrees C were obtained in the BZT ceramics with 11 wt% BCB2 sintered at 900 degrees C for 2h. It was suitable for the low temperature co-fired ceramics (LTCC) applications. (C) 2015 Elsevier Ltd. All rights reserved.