The invention relates to a thick-film type limited current
hydrogen sensor and a preparation method thereof, belonging to the technical field of electrochemical gas sensors. The sensor consists of dense
proton conductor slices and dense
proton /
electron mixed thick conductor films or dense
proton /
electron mixed conductor slices and dense thick conductor films. The composition of the
proton conductor slices is AB(1-x)RxO(3-
delta)(x is more than or equal to 0 and less than or euqal to 0.3), wherein A is Ca, Sr or Ba; B is one or more of Ce, Zr, Nb and Ti; and R is one or more of Sc, Y, La, Pr, Nd, Dy, Ho, Er, Lu, Gd and In. The composition of the proton /
electron mixed conductor slices is AB(1-x)R'xO(3-
delta) (x is more than or equal to 0 and less than or euqal to 0.3), wherein A is Ca, Sr or Ba; B is one or more of Ce, Zr, Nb and Ti; and R' is one or more of Sm, Eu, Tb, Yb, Tm, Mn and Ti. The preparation method of the sensor comprises the following steps: preparing two kinds of conductor
powder; preparing the dense proton conductors and the dense proton / electron
mixed conductor slices; preparing thick films by a screen print technology; and assembling the sensor. The sensor is suitable for the detection of
hydrogen in gas.