Field‐orientedY1Ba2Cu3Oysamples with various values of the transport critical current density,Jc, have been prepared with various heat treatments. TheJcincreased rapidly with an increase in relative sintered density of the oriented samples. The field‐oriented samples with higherJchad grains of larger sizes and better connections between the neighboring grains than the lowJcsamples. The maximum values ofJcat a magnetic field of 7 T were 370 A/cm2at 4.2 K and 24 A/cm2at 77 K. The hysteresis in theJc‐Hcurves at 4.2 K decreased with an increase inJcboth for an applied fieldH∥abplane and forH∥caxis. The critical currents of the samples with higherJcwere less degraded by aging in the air for 1 year than those of the lowJcsamples. The relation between the field‐cooledJc‐Hcurves and the zero‐field‐cooled ones for an oriented sample with lowJcis qualitatively interpreted by the effect of the intragrain currents on the intergrain fields.